The most common and most likely answer to this crossword clue is the 7 letter word PARVENU
I've seen this crossword clue in The Guardian
P
A
R
V
E
N
U
More clues leading to the result PARVENU
- Usual meeting place not quite enough for social climber
- Arriviste from north in disorderly rave-up
- Upstart after a year runs meeting-place briefly
- Newcomer‘s music upset audience finally leaving concert hall, say
- Nouveau riche location second to be struck off, substandard
- Social climber in usual place, snubbed
- Drug dropped in normal place for someone not yet accepted
- Average goddess curtailed by new arrival
- PARVENU
- Vulgarian charge overturned prior to brief rendezvous
Buddy explains!

The straight part
We know that "Newcomer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case newcomer = parvenu.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PARVENU mean?
PARVENU noun- A person who has risen, climbed up, or has been promoted to a higher social class, especially through acquisition of wealth, rights, or political authority but has not gained social acceptance by those within that new class.
- Being a parvenu; also, like, having the characteristics of, or associated with a parvenu.